Page 44 - RoadCem Manual - PCT BV

As can be seen the damage effect of 1 truck is comparable to 10.000 cars. Therefore, in road engineering the loads during the life span on the pavements are estimated by the number of trucks and not by the number of cars.
Calculating the axle load repetitions
To determine the amount of axle load repetitions it is important to know how much truck traffic can be expected driving in the lanes with the heaviest loads. How heavy the trucks are when loaded, the expected traffic growth over the design lifetime for the pavement and the expected lifespan of the pavement are all to be taken into consideration The following formula is used to determine the amount of standard maximum axle load repetitions:
 GL 1+100 −1
Neq =V⋅W⋅Fs⋅Fs⋅Dv⋅Fv⋅ G 100
Where Neq =
V =
W =
Fs = Fv = Fr = Dv = G = L =
Total amount standard axle load repetitions.
Number of trucks per 24 hours.
Number of work days per year.
Correction factor for the amount of driving lanes per year. Correction factor for the driving lane width.
Speed of the heavy goods traffic. Truck damage factor.
Growth.
Life span.
The different variables and typical design values are discussed below.
Trucks, number (V)
Generally the client has an indication of the number of trucks that are expected to use the road. In suburban areas typically there are limited numbers (e.g. refuse trucks, fire-engines, etc), 2 trucks per 24 hours is a good assumption. On the highway the number of trucks expected is much higher, varying from 500 to 20.000 per 24 hours.
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